1. Field of the Invention
The present invention relates to a lockset knob assembly for use with an interchangeable lock core.
2. Description of the Related Art
Locks allowing interchanging of lock cores have been used, and two typical types thereof include knobs and lever handles for receiving the interchangeable lock cores. FIGS. 5 through 7 of the drawings illustrates a conventional lockset knob assembly for use with an to interchangeable lock core. The lockset knob assembly includes an outer knob housing 80, an inner knob housing 81, a sleeve 82, and a spindle 83 that is operably connected with a transmission shaft of a lockset transmission assembly. The lockset is unlatched when the spindle 83 is turned. The sleeve 82 is mounted in the spindle 83 and includes a number of inner radial protrusions 831 for positioning the sleeve 82. As illustrated in FIGS. 5 and 6, the spindle 83 includes a number of longitudinal projections 832 that are extended through associated slots 811 in the inner knob housing 81 and then bent so as to be positioned in associated grooves 812 in the inner knob housing 81. As illustrated in FIGS. 5 and 6, the inner knob housing 81 is inserted into the outer knob housing 80 via an opening in an end of the outer knob housing 80 with an 8-shape hole 813 in an end face of the inner knob housing 81 aligned with an 8-shape hole 802 in an end face of the outer knob housing 80. Then, the outer knob housing 80 is rolled to reduce the diameter of the opening 801, thereby enclosing the inner knob housing 81.
After mounting a lock core 84 via the 8-shape holes 813 and 802, a proper key is inserted into the lock core 84 and then rotated through a pre-determined angle to make a wing 841 project outward and be located behind the sleeve 82, thereby preventing disengagement of the lock core 84. Replacement of the lock core 84 can be easily achieved by means of inserting the proper key into the lock core 84 and rotating the key through the pre-determined angle in a reverse direction until the wing 841 retracts into the lock core 84 to thereby allow removal of the lock core 84 and subsequent insertion of a new lock core.
Nevertheless, when removing the lock core 84, the sleeve 82 may be rotated inadvertently and thus hinder insertion of the new lock core, as a central portion of the sleeve 82 no longer aligns with a lower portion of the 8-shape hole 813 of the inner knob housing 81. In addition, since the inner knob housing 81 and the outer knob housing 80 are not positioned relative to each other, the inner knob housing 81 and the outer knob housing 80 may be moved relative to each other during rolling of the outer knob housing 80, such that the 8-shape holes 813 and 802 thereof no longer align with each other. Additional adjustment for re-achieving the alignment of the 8-shape holes 813 and 802 is required. Furthermore, the inner and outer knob housings 80 and 81 are formed by means of punching and rolling thin metal plates and are thus very thin, especially in the 8-shape holes 802 and 813. As a result, even though a lock core 84 is mounted in the 8-shape holes 802 and 813, the lockset can be picked easily by means of inserting a sharp article through a point A in FIG. 6 to damage the outer end face of the outer knob housing 80 and then the lock core 84 and the inner knob housing 81.
A lockset knob assembly in accordance with the present invention comprises:
an outer knob housing including a first end with a first opening and a second end with a first 8-shape hole in an end face of the second end, a periphery defining the first 8-shape hole including a retaining flange projecting inward toward the first end of the outer knob housing;
an inner knob housing including a first end with a second opening and a second end with a second 8-shape hole in an end face of the second end, the second 8-shape hole being larger than the first 8-shape hole, the inner knob housing being mounted in the outer knob housing with the retaining flange of the outer knob housing engaged in the second 8-shape hole to thereby prevent relative movement between the inner knob housing and the outer knob housing, the inner knob housing further including a plurality of slots and a plurality of radially extending grooves, each said groove being adjacent to and communicated with an associated said slot;
a spindle including a plurality of longitudinal projections that are extended through the slots of the inner knob housing and then bent so as to be positioned in the grooves of the inner knob housing, respectively, the spindle further including a first engaging portion; and
a sleeve mounted in the spindle and including a second engaging portion that is engaged with the first engaging portion, thereby preventing longitudinal movement and rotational movement of the sleeve relative to the spindle.
The first engaging portion is a protrusion and the second engaging portion is an engaging slot for engaging with the protrusion. Alternatively, the first engaging portion is an engaging slot and the second engaging portion is a protrusion for engaging with the engaging slot.
In accordance with the present invention, the sleeve of the lockset knob assembly is reliably positioned so as not to interfere with changing of the lock core. The retaining flange that projects inward from a periphery defining the 8-shape hole of the outer knob housing engages with a periphery defining the 8-shape hole of the inner knob housing to thereby prevent relative movement between the inner knob housing and the outer knob housing during the rolling procedure for enclosing the inner knob housing by the outer knob housing. In addition, the thickness of the periphery defining the 8-shape hole of the outer knob housing is increased and the strength thereof is improved to prevent picking of and damage to the lockset.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.